1. Field of the Invention
The invention relates to adding and dispersing small catalyst particles in a hydrocarbon liquid. More particularly the invention relates to a process for adding and dispersing a small particle size Fischer-Tropsch catalyst in a hydrocarbon slurry in a Fischer-Tropsch hydrocarbon synthesis reactor, by forming a mixture of the particles and a liquid, non-acidic, polar oxygenate, preferably a one to four carbon atom alcohol, and adding the mixture to the slurry.
2. Background of the Invention
It is known to conduct chemical processes and reactions in a slurry comprising particulate solids dispersed or suspended in a slurry liquid. Such processes include hydroprocessing reactions, in which hydrogen or a hydrogen containing treat gas is reacted with a hydrocarbonaceous feed in the presence of a particulate catalyst dispersed in a hydrocarbon liquid, to convert the molecular structure of at least a portion of the feed. Also known is a slurry Fischer-Tropsch hydrocarbon synthesis processes, in which a synthesis gas comprising a mixture of H.sub.2 and CO is bubbled up into a hydrocarbon slurry liquid in which is dispersed a particulate Fischer-Tropsch type of hydrocarbon synthesis catalyst. The H.sub.2 and CO react in the presence of the catalyst to form hydrocarbons, at least a portion of which are liquid at the reaction conditions and form the hydrocarbon slurry liquid. In a hydroprocessing or slurry Fischer-Tropsch hydrocarbon synthesis reactor, the three phases of gas, liquid and solids form a three phase slurry. Such reactors are sometimes referred to as ebulating bed reactors, in which upflowing gas and/or liquid serve to expand and disperse the particulate solids which can comprise either part of the feed (e.g., coal liquefaction) or catalyst, or other particles (such as heat transfer particles), for various hydrogenation and hydrocracking reactions. Such reactions include, in addition to coal liquefaction, hydrogenation, resid fining and other hydrogenation reactions. Reactors which contain a three phase slurry of gas bubbles and particles in a slurry liquid are sometimes referred to as "bubble columns" or "slurry bubble columns", as is disclosed in U.S. Pat. No. 5,348,982. Irrespective of whether a slurry reactor is operated as a dispersed or slumped bed, vigorous three directional mixing conditions are present in the slurry, typically somewhere between the two theoretical conditions of plug flow and back mixed. In all of these processes it is necessary to add fresh or regenerated catalyst particles to the hydrocarbon slurry liquid either continuously or intermittently. For example, U.S. Pat. No. 5,466,362 is typical of the prior art in which catalyst addition to a hydrocarbon slurry is achieved by wetting and slurrying fresh, dry catalyst particles with the hydrocarbon feed liquid and then adding the fresh catalyst slurry to the reactor. However, it has been found that this method is not satisfactory for the case of small particle size catalysts, which are not easily wet by hydrocarbon liquids and which, instead of dispersing, clump up in a hydrocarbon liquid, even under conditions of vigorous stirring or agitation.